linux-kernel - Re: rename probe_kernel_* and probe_user

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Message-ID: <87lfkjd19d.fsf@mpe.ellerman.id.au>
Date:   Fri, 19 Jun 2020 16:21:18 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Christoph Hellwig <hch@....de>,
        Russell King <linux@...linux.org.uk>,
        Tony Luck <tony.luck@...el.com>, Helge Deller <deller@....de>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-ia64@...r.kernel.org, linux-parisc@...r.kernel.org,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        the arch/x86 maintainers <x86@...nel.org>
Subject: Re: rename probe_kernel_* and probe_user_*

Linus Torvalds <torvalds@...ux-foundation.org> writes:
> [ Explicitly added architecture lists and developers to the cc to make
> this more visible ]
>
> On Wed, Jun 17, 2020 at 12:38 AM Christoph Hellwig <hch@....de> wrote:
>>
>> Andrew and I decided to drop the patches implementing your suggested
>> rename of the probe_kernel_* and probe_user_* helpers from -mm as there
>> were way to many conflicts.  After -rc1 might be a good time for this as
>> all the conflicts are resolved now.
>
> So I've merged this renaming now, together with my changes to make
> 'get_kernel_nofault()' look and act a lot more like 'get_user()'.
>
> It just felt wrong (and potentially dangerous) to me to have a
> 'get_kernel_nofault()' naming that implied semantics that we're all
> familiar with from 'get_user()', but acting very differently.
>
> But part of the fixups I made for the type checking are for
> architectures where I didn't even compile-test the end result. I
> looked at every case individually, and the patch looks sane, but I
> could have screwed something up.
>
> Basically, 'get_kernel_nofault()' doesn't do the same automagic type
> munging from the pointer to the target that 'get_user()' does, but at
> least now it checks that the types are superficially compatible.
> There should be build failures if they aren't, but I hopefully fixed
> everything up properly for all architectures.
>
> This email is partly to ask people to double-check, but partly just as
> a heads-up so that _if_ I screwed something up, you'll have the
> background and it won't take you by surprise.

The powerpc changes look right, compile cleanly and seem to work
correctly.

cheers